On Thu, May 08, 2008 at 09:54:28AM +0200, Juergen Beisert wrote: > It seems the documentation in the "asoc-v2-dev" > (Documentation/sound/alsa/soc/) is still v1, isn't it? Yes. > I'm confused how to link the pcm-layer and the transmission layer together. > pxa2xx-i2s.c registers a codec-dai (line 346), while the imx-ssi.c registers > (line 864) a platform-dai (internally called a cpu_dai. BTW: why a different > name?). I _believe_ the CPU DAI tries to connect the CPU-pcm to the > transmission interface like ssi or i2s on the same chip. But both > implementations are using the same layering (pcm-dma and ssi/i2s), but > registering different DAIs. The i.MX code is correct here. The PXA I2S code isn't a good example to use - it doesn't compile at the minute due to changes in the underlying PXA platform code - and has only been translated mechanically for ASoC v2. If you're looking for examples then the most heavily tested in-tree configurations for ASoC v2 are: - i.MX31 I2S with WM8350 - PXA3xx AC97 with WM9713 > Now I have an ssi driver for my CPU (to be more precise: Two instances of it, > when I registering two ssi devices in my BSP file). But how to tell the CPU > pcm-layer which one it should use (and for what purpose, play, capture)? And > only the ssi driver itself knows how to interact with the DMA controller. But > this information is needed in the CPU pcm-layer as it setup the DMA. The CPU DAI has a dma_data member intended for this purpose - it can set up information the DMA driver will need in there for the DMA driver to pick up when it needs it. The PXA code sets this up in hw_params since the DMA configuration depends on if the stream is mono or stereo but there's no need to set it up that late if you don't have a similar requirement. > Does a list exists, where I can store driver's private data in each layer > (mapped iomem addresses for example)? And how to access it, when I only get > a "struct snd_pcm_substream" as a parameter? Yes. ASoC sets the private_data of snd_pcm_substream to point to the struct snd_soc_pcm_runtime for the substream. That in turn contains pointers to the platform, codec and CPU DAIs. Each of those has a private_data member which you can use. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
